The invention generally relates to a process for producing sanded elastic fabrics, and sanded elastic fabrics having improved aesthetic characteristics. More specifically, the invention relates to a process for producing sanded elastic fabrics at increased levels of quality and levels of efficiency, and sanded, elastic fabrics having good hand, low fuzz level, and consistent nap density and height across the width of the fabric.
Knit fabrics are commonly used in a variety of end uses, such as industrial products, apparel and the like. One advantage associated with knit fabrics is that they can be constructed to have good stretch characteristics. Such characteristics of a knit fabric can be enhanced through the use of elastic fibers in the fabric. For example, elastic fibers such as spandex are now often included in knit fabrics to provide the fabrics with a high degree of stretch. These fabrics are particularly desirable in the manufacture of intimate apparel items, bathing suits and the like since they allow the manufacturer to vary the amount of compression and support which the garments will provide.
When using fabrics in end uses such as apparel, it is often desired to treat the fabric in some way to improve its hand. For example, fabrics are often treated mechanically, such as by sanding or otherwise abrading the fibers on the surface of the fabric to provide the surface with a softer feel. Such face finishing processes can be performed on one or both surfaces.
Conventional sanding processes for textile fabrics are commonly performed by contacting one or both fabric surfaces with a roller which has been covered with sandpaper. While performing well in some applications, this method can be difficult to use on elastic fabrics, and in particular, on elastic knit fabrics. (As used herein, the term xe2x80x9celastic fabricsxe2x80x9d is meant to describe those fabrics containing elastic fibers, and the term xe2x80x9celastic knit fabricsxe2x80x9d is intended to describe knit fabrics incorporating elastic fibers, regardless of the manner in which they are knit.) For one, the sandpaper has a tendency to become loaded up with abraded fiber material very quickly, which requires that the paper be removed and new sandpaper applied. For example, the sandpaper on a roll used to process elastic fiber-containing knit fabrics can typically only process about 5,000 yards of fabric before it becomes so loaded with particles from the fabric that it must be replaced.
In addition, it can be difficult to impossible to achieve a consistent nap across the width of the fabric (i.e., the direction perpendicular to that of fabric travel during processing), which leads to what is referred to as a high degree of side-center-side variation. As can be readily appreciated by those of ordinary skill in the art, fabrics which are inconsistent are generally undesirable for many end uses as they do not provide a consistent appearance or consistent performance. This is a particular problem for elastic knit fabrics, as they have a tendency to neck down in the center during the face finishing operation, resulting in the selvages of the fabric being sanded more than the center of the fabric. Consequently, the center of the fabric can tend to look pitted, which is undesirable from a fabric quality perspective.
Even more importantly, knit fabric manufacturers have heretofore been unable to produce sanded elastic fabrics which do not have a high amount of fuzz on the fabric surface. Such fuzz (which is a result of fiber breakage, can be unappealing from an aesthetic perspective, and can encourage pilling of the fabrics during use. In an attempt to minimize the fuzzing effect to the extent possible, manufacturers typically are forced to sand the sandpaper itself prior to using it on the elastic knit fabrics in order to remove the sharp points on the sandpaper grit. Even with the inclusion of this additional processing step (which in turn adds cost to the manufacturing operation), the amount of fuzzing achieved is still greater than what would be desired.
The instant invention enables the manufacture of a sanded elastic fabric which has a good feel and which does not have an undesirable fuzzy appearance. In addition, the instant invention achieves fabrics having good side-center-side consistency, both in terms of nap density and nap height. Furthermore, the process of the invention enables the production of higher quality sanded elastic fabrics at increased levels of efficiency.
The process of the invention involves the use of a microfinishing film on the roller of a conventional sanding or sueding machine. To the knowledge of the inventors, such films have not previously been used to process textile fabrics, rather they have been used to sand metal parts, solid surface composites, fiberglass, paints and plastics. The fabric is then sanded with the microfinishing film, which functions to loosen the fibers in the yarn bundles without undesirably cutting them in the manner of conventional sandpaper.
It has been found that microfinishing films do not load up as readily as conventional sandpaper, such that a significantly greater quantity of fabric can be processed before replacement of the film is required. For example, it has been found that 20,000 yards of a fabric can be processed by the microfinishing film whereas only 5,000 yards of the same fabric could be processed with conventional sandpaper before replacement of the sanding medium was required.